Rust engineers, meet Kache 🦀 less duplicated target/, faster builds

[0FlorDelgado]

Hi Rust folks,

We recently shared Kache, an open-source, zero-copy, content-addressed build cache for Rust.

More info: https://kunobi.ninja/product/kache
GitHub: https://github.com/kunobi-ninja/kache

Kache focuses on a common pain in Rust workflows: duplicated build artifacts, heavy target/ directories, multiple worktrees, and CI/local setups where the same compilation outputs may be rebuilt or stored multiple times.

It works as a RUSTC_WRAPPER, keeps the standard Cargo workflow, and restores cache hits using hardlinks locally, with optional S3-compatible storage for CI environments.

We’re opening this discussion to collect technical feedback from the Rust community, understand real-world use cases, and answer questions directly with our engineering team.

[0FlorDelgado]

Some questions and topics already came up from the community after sharing Kache:

1. How does Kache compare to using a single global Cargo target directory instead of per-crate or per-workspace targets?
2. How does Kache compare with sccache, and what benchmark scenarios would be useful?
3. How can Kache help with Rust builds in GitHub Actions and CI caching workflows?
4. What are the practical tradeoffs around speed, disk usage, isolation, cleanup, and CI behavior?

We’re using this discussion as a place to centralize those questions, collect technical feedback, and answer directly with our engineering team.

[0FlorDelgado]

5. How should Kache behave at larger scales, including Crater-scale runs, polyglot projects, real-world edge cases, and blob inclusion?

[jleni]

Moved questions to https://github.com/orgs/kunobi-ninja/discussions/categories/q-a-kache?discussions_q=is%3Aopen+category%3A%22Q%26A+-+Kache%22 so we can address them separately